Chris@49: // Copyright (C) 2009-2012 NICTA (www.nicta.com.au)
Chris@49: // Copyright (C) 2009-2012 Conrad Sanderson
Chris@49: // 
Chris@49: // This Source Code Form is subject to the terms of the Mozilla Public
Chris@49: // License, v. 2.0. If a copy of the MPL was not distributed with this
Chris@49: // file, You can obtain one at http://mozilla.org/MPL/2.0/.
Chris@49: 
Chris@49: 
Chris@49: //! \addtogroup op_mean
Chris@49: //! @{
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! \brief
Chris@49: //! For each row or for each column, find the mean value.
Chris@49: //! The result is stored in a dense matrix that has either one column or one row.
Chris@49: //! The dimension, for which the means are found, is set via the mean() function.
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: void
Chris@49: op_mean::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_mean>& in)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const unwrap_check<T1> tmp(in.m, out);
Chris@49:   const Mat<eT>& X = tmp.M;
Chris@49:   
Chris@49:   const uword dim = in.aux_uword_a;
Chris@49:   arma_debug_check( (dim > 1), "mean(): incorrect usage. dim must be 0 or 1");
Chris@49:   
Chris@49:   const uword X_n_rows = X.n_rows;
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   
Chris@49:   if(dim == 0)
Chris@49:     {
Chris@49:     arma_extra_debug_print("op_mean::apply(), dim = 0");
Chris@49:     
Chris@49:     out.set_size( (X_n_rows > 0) ? 1 : 0, X_n_cols );
Chris@49:     
Chris@49:     if(X_n_rows > 0)
Chris@49:       {
Chris@49:       eT* out_mem = out.memptr();
Chris@49:       
Chris@49:       for(uword col=0; col < X_n_cols; ++col)
Chris@49:         {
Chris@49:         out_mem[col] = op_mean::direct_mean( X.colptr(col), X_n_rows );
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:   if(dim == 1)
Chris@49:     {
Chris@49:     arma_extra_debug_print("op_mean::apply(), dim = 1");
Chris@49:     
Chris@49:     out.set_size(X_n_rows, (X_n_cols > 0) ? 1 : 0);
Chris@49:     
Chris@49:     if(X_n_cols > 0)
Chris@49:       {
Chris@49:       eT* out_mem = out.memptr();
Chris@49:       
Chris@49:       for(uword row=0; row < X_n_rows; ++row)
Chris@49:         {
Chris@49:         out_mem[row] = op_mean::direct_mean( X, row );
Chris@49:         }
Chris@49:       }
Chris@49:     }
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: arma_pure
Chris@49: inline
Chris@49: eT
Chris@49: op_mean::direct_mean(const eT* const X, const uword n_elem)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const eT result = arrayops::accumulate(X, n_elem) / T(n_elem);
Chris@49:   
Chris@49:   return arma_isfinite(result) ? result : op_mean::direct_mean_robust(X, n_elem);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: arma_pure
Chris@49: inline
Chris@49: eT
Chris@49: op_mean::direct_mean_robust(const eT* const X, const uword n_elem)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   // use an adapted form of the mean finding algorithm from the running_stat class
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   uword i,j;
Chris@49:   
Chris@49:   eT r_mean = eT(0);
Chris@49:   
Chris@49:   for(i=0, j=1; j<n_elem; i+=2, j+=2)
Chris@49:     {
Chris@49:     const eT Xi = X[i];
Chris@49:     const eT Xj = X[j];
Chris@49:     
Chris@49:     r_mean = r_mean + (Xi - r_mean)/T(j);    // we need i+1, and j is equivalent to i+1 here
Chris@49:     r_mean = r_mean + (Xj - r_mean)/T(j+1);
Chris@49:     }
Chris@49:   
Chris@49:   
Chris@49:   if(i < n_elem)
Chris@49:     {
Chris@49:     const eT Xi = X[i];
Chris@49:     
Chris@49:     r_mean = r_mean + (Xi - r_mean)/T(i+1);
Chris@49:     }
Chris@49:   
Chris@49:   return r_mean;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: op_mean::direct_mean(const Mat<eT>& X, const uword row)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   
Chris@49:   eT val = eT(0);
Chris@49:   
Chris@49:   uword i,j;
Chris@49:   for(i=0, j=1; j < X_n_cols; i+=2, j+=2)
Chris@49:     {
Chris@49:     val += X.at(row,i);
Chris@49:     val += X.at(row,j);
Chris@49:     }
Chris@49:   
Chris@49:   if(i < X_n_cols)
Chris@49:     {
Chris@49:     val += X.at(row,i);
Chris@49:     }
Chris@49:   
Chris@49:   const eT result = val / T(X_n_cols);
Chris@49:   
Chris@49:   return arma_isfinite(result) ? result : op_mean::direct_mean_robust(X, row);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: op_mean::direct_mean_robust(const Mat<eT>& X, const uword row)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   
Chris@49:   eT r_mean = eT(0);
Chris@49:   
Chris@49:   for(uword col=0; col < X_n_cols; ++col)
Chris@49:     {
Chris@49:     r_mean = r_mean + (X.at(row,col) - r_mean)/T(col+1);
Chris@49:     }
Chris@49:   
Chris@49:   return r_mean;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline
Chris@49: eT
Chris@49: op_mean::mean_all(const subview<eT>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const uword X_n_rows = X.n_rows;
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   const uword X_n_elem = X.n_elem;
Chris@49:   
Chris@49:   arma_debug_check( (X_n_elem == 0), "mean(): given object has no elements" );
Chris@49:   
Chris@49:   eT val = eT(0);
Chris@49:   
Chris@49:   if(X_n_rows == 1)
Chris@49:     {
Chris@49:     const Mat<eT>& A = X.m;
Chris@49:     
Chris@49:     const uword start_row = X.aux_row1;
Chris@49:     const uword start_col = X.aux_col1;
Chris@49:     
Chris@49:     const uword end_col_p1 = start_col + X_n_cols;
Chris@49:     
Chris@49:     uword i,j;
Chris@49:     for(i=start_col, j=start_col+1; j < end_col_p1; i+=2, j+=2)
Chris@49:       {
Chris@49:       val += A.at(start_row, i);
Chris@49:       val += A.at(start_row, j);
Chris@49:       }
Chris@49:     
Chris@49:     if(i < end_col_p1)
Chris@49:       {
Chris@49:       val += A.at(start_row, i);
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     for(uword col=0; col < X_n_cols; ++col)
Chris@49:       {
Chris@49:       val += arrayops::accumulate(X.colptr(col), X_n_rows);
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   const eT result = val / T(X_n_elem);
Chris@49:   
Chris@49:   return arma_isfinite(result) ? result : op_mean::mean_all_robust(X);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline 
Chris@49: eT
Chris@49: op_mean::mean_all_robust(const subview<eT>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const uword X_n_rows = X.n_rows;
Chris@49:   const uword X_n_cols = X.n_cols;
Chris@49:   
Chris@49:   const uword start_row = X.aux_row1;
Chris@49:   const uword start_col = X.aux_col1;
Chris@49:   
Chris@49:   const uword end_row_p1 = start_row + X_n_rows;
Chris@49:   const uword end_col_p1 = start_col + X_n_cols;
Chris@49:   
Chris@49:   const Mat<eT>& A = X.m;
Chris@49:   
Chris@49:   
Chris@49:   eT r_mean = eT(0);
Chris@49:   
Chris@49:   if(X_n_rows == 1)
Chris@49:     {
Chris@49:     uword i=0;
Chris@49:     
Chris@49:     for(uword col = start_col; col < end_col_p1; ++col, ++i)
Chris@49:       {
Chris@49:       r_mean = r_mean + (A.at(start_row,col) - r_mean)/T(i+1);
Chris@49:       }
Chris@49:     }
Chris@49:   else
Chris@49:     {
Chris@49:     uword i=0;
Chris@49:     
Chris@49:     for(uword col = start_col; col < end_col_p1; ++col)
Chris@49:     for(uword row = start_row; row < end_row_p1; ++row, ++i)
Chris@49:       {
Chris@49:       r_mean = r_mean + (A.at(row,col) - r_mean)/T(i+1);
Chris@49:       }
Chris@49:     }
Chris@49:   
Chris@49:   return r_mean;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline 
Chris@49: eT
Chris@49: op_mean::mean_all(const diagview<eT>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const uword X_n_elem = X.n_elem;
Chris@49:   
Chris@49:   arma_debug_check( (X_n_elem == 0), "mean(): given object has no elements" );
Chris@49:   
Chris@49:   eT val = eT(0);
Chris@49:   
Chris@49:   for(uword i=0; i<X_n_elem; ++i)
Chris@49:     {
Chris@49:     val += X[i];
Chris@49:     }
Chris@49:   
Chris@49:   const eT result = val / T(X_n_elem);
Chris@49:   
Chris@49:   return arma_isfinite(result) ? result : op_mean::mean_all_robust(X);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: inline 
Chris@49: eT
Chris@49: op_mean::mean_all_robust(const diagview<eT>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename get_pod_type<eT>::result T;
Chris@49:   
Chris@49:   const uword X_n_elem = X.n_elem;
Chris@49:   
Chris@49:   eT r_mean = eT(0);
Chris@49:   
Chris@49:   for(uword i=0; i<X_n_elem; ++i)
Chris@49:     {
Chris@49:     r_mean = r_mean + (X[i] - r_mean)/T(i+1);
Chris@49:     }
Chris@49:   
Chris@49:   return r_mean;
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T1>
Chris@49: inline
Chris@49: typename T1::elem_type 
Chris@49: op_mean::mean_all(const Base<typename T1::elem_type, T1>& X)
Chris@49:   {
Chris@49:   arma_extra_debug_sigprint();
Chris@49:   
Chris@49:   typedef typename T1::elem_type eT;
Chris@49:   
Chris@49:   const unwrap<T1>   tmp(X.get_ref());
Chris@49:   const Mat<eT>& A = tmp.M;
Chris@49:   
Chris@49:   const uword A_n_elem = A.n_elem;
Chris@49:   
Chris@49:   arma_debug_check( (A_n_elem == 0), "mean(): given object has no elements" );
Chris@49:   
Chris@49:   return op_mean::direct_mean(A.memptr(), A_n_elem);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename eT>
Chris@49: arma_inline
Chris@49: eT
Chris@49: op_mean::robust_mean(const eT A, const eT B)
Chris@49:   {
Chris@49:   return A + (B - A)/eT(2);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: template<typename T>
Chris@49: arma_inline
Chris@49: std::complex<T>
Chris@49: op_mean::robust_mean(const std::complex<T>& A, const std::complex<T>& B)
Chris@49:   {
Chris@49:   return A + (B - A)/T(2);
Chris@49:   }
Chris@49: 
Chris@49: 
Chris@49: 
Chris@49: //! @}
Chris@49: